Actress Kelley Mack's death came as a shock to those in her inner circle after she underwent treatment during her glioma battle. A rep for the Walking Dead alum told TMZ that her death was a "total" surprise,

Actor Kelley Mack, best known for playing Addy on "The Walking Dead," died over the weekend, her family announced. She was 33. "Such a bright, fervent light has transitioned to the beyond, where we all eventually must go," her sister Kathryn wrote on her Instagram page Tuesday.

Actress Kelley Mack was starting to become a regular presence on our TV screens before her death at age 33. Mack got her start in short films and small TV roles before joining bigger productions like The Walking Dead, 9-1-1 and Chicago Med. She was outspoken about how playing Addy on the post-apocalyptic show introduced her to an online fanbase.